Juan Pizarro y Alonso (Spanish: [xwam piˈθaro]; born c. 1511 in Trujillo; died July 1536) was a Spanish conquistador who accompanied his brothers Francisco, Gonzalo and Hernando Pizarro for the conquest of Peru in 1532.
His father was a colonel of infantry who had served with distinction in the Italian campaigns under Gonzalo Fernández de Córdoba, and in Navarre.
Juan and his brothers, led by Francisco and friend Diego de Almagro, conquered the mighty Inca Empire in 1533, not only by virtue of being heavily armed but also as smallpox was spread among the natives, killing many.
Hernando, Gonzalo and Juan led the defense with counterattacks on the fortress overlooking the city.
Unable to wear a helmet (his jaw was swollen after being hit by a slingshot), Juan was struck in the head by a large stone and died a fortnight later.